Dental chair.



F. E. CASE. DENTAL' CHAIR. APPLIQATION ump JUNE 25. 190s.

Patented Jan. 19. 1909.

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DENTAL CHAIR.

APPLICATION FILED JUNI: 25. 190s.

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Patented Jan. 19. 1909. 3 SHEETS-SHEET 31 zyl , /rwewfor @aA/ef moved from its soeket;l `ig. 8, afragmvnhn'y heads being considerably smaller than the 110 \l\2 j l l l NITED sTArEs PrENr OFFICE.

FRANK E. CASE, OF CANTON, OHIO, ASSIGNOR TO THE HARVARD COMPANY, 0F CANTON, OHIO, A CORPORATION 4OF OHIO.

DENTAL CHAIR.

4Specification o! Letters I jatent.

Patented Jan. 19I 1909.

Application filed June 1906. Serial No. 323,218.

To all whom 'it may concern.'

Be -it known that I, FRANK E. CASE, a citizen of the United States, residing at Canton, in the county of Stark and State of Ohio, have invented a new and useful Imrovementdn Dental Chairs, of which the Following is a specification. 1

The invention relates to chairs of the kind enerall used by dentists, surgeons, barers ana others, wherein the back and other parts hre adjustable with reference to the.

seat, so that the bod and legs of th patient or other occupant o the chair can be transosed from an erect to a reclining position. In such chairs it is desirable to connect the back, with the headrest thereon, to the seat in such a manner that when the back is adjusted to accommodate the various posi tions of the occupant, the headrest will travel substantially in the locus of the occuant s head, so that it will not be necessary -or the occupant to shift his position er1-the seat to preserve the osition of his head upon the rest. This o ject is attained by joining the back to the seat by a slidable connection formed on the arc of a circle having its center located over the seat approximately'in the position ol' the hip joint of the occupant.

Other features of invention relate to the adjustment of the back on its supporting shank; and the use of a substitute or secondary seat for children, who are not large enough to occupy the ordinary seat.

These several objects are attained by the construction, mechanism and arrangement illustrated in the accompanying drawings, in which- Figure 1 is a side elevation of thc chair seat and other u per parts, showing the back-bracket party in section; Fig. 2, a cross section of the back-bracket and the shank-slide therein, on line 2h2, Fig. 1; Fig. 3, a vertical median-line sect-ion of the back, its bracket and the adjoining iai-t of the seat; Fig. 4, a pers cctivo riglit-rr'ar view of the upper part of t e chair, with the ordinary scat propel' removed and thi` secondary seat 1n position for use; Fier. 5, a detached perspective view showing detailsof the secondary scat n'ilh its parte sopa-- rated; Figi 6, a framncntary View showing;4 tho bark-shank locking; li-vire, l"i 7, :i

section on lines 8 8, liij.` 6, showing the wedge-block in its socket; ig. 9, a side view of the lower part of the back-shank; Fig. 10, a detached perspective view of the shanklatch showing its parts separated; Fi 11, a detached perspective view of the hea rest shank; Fig. 12, a fragmentary vertical section showing the method of locking the head-rest shank to the back-slide; Fig. 13, a cross-section on line 13-13, Fig. 12; and Fig. 14, a detached perspective view of the back-adjusting rack.

Similar numerals refer to similar parts throughout the drawings.

In the seat-frame 1 is provided the backbracket 2 in which is formed the T-shaped slide-channel 3 o ening downward and ex tending longitudlnally backward and upward along the are of a circle having its center, as at 4, well forward and over the seat cushion. The small lohgitudinal groove 5 is preferably rovided in bottom of the slide-channel an when used terminates at a point, as at 6, adjacent to the rear end of the channel. When only one backbracket is provided, the same is preferably located in the median line of the satframe.

The lower end of the back-shank 7 is curved downward and forward andI is formed T-sha e in cross-section so as to neatl fit and s 1de longitudinally in the channel o the back-bracket. The ordinary sprin latch 8 is provided in the shank-slide an its forward end is adapted to normally enter and operate in the c annelroove 5, and to be stopped at the upper en 6 thereof whereby the upward movement of the slide can be limited; but by pulling the latch out of the groove, the slide is free to he removed from or entered in the channel as may be desired.

'lhe back-shank is locked at any desired position in the hack-bracket by means of the wcdgeblock El located in the similar recess l0 in one side of the concave face of the shankslide, which block is adapted to be forced toward the adjoining wall of the slide-cham ncl by the screw 11 aving the handle 12 l0- catcd to bc conveniently accessible to the operator of the chair. rlhe wedge-blocky may he held in proximate position b the rivet 13 passed through the cone-shaped)apertures 14 and 14 in the block and slide, the shank of thc rivet being slightly smaller than the adsimilar View showing the wcdgri-ldorh |rjoining small ends of the apertures, and the enlarged mittingi block. By means of the slidable connection. on the arc of a circle thus described, when the back is adjusted rearward it is also carried slightly downward and accommodates itself to the normal movement of the back of the occupant of the chair in reclining backward; and this is accomplished without the use ol pivots at the sides of the chair.

The bak roper 15 is pivoted at the u per end of the s 1de 16, as at 17, and this sli e is adapted to be retained and to operate lon itudmally in the channel 18 in the back-shangk whereby the back can be adjusted up ant down. The back may be locked at any desired point of adjustment by means of the handled screw 19 in the slide, which screw is provided with the annular shoulder 2() adapted to bear a ainst the friction-block 21 and parts of the apertures, thereby perthe end 22 o the screw is adapted to operato l and forward in the channel e slight movement required of the l in the groove 23 in the bottom of the shank i e and to be stopped aeainst the upper l chann end 24 of this groove, whie i sto limits the upward adjustment o the back, and its downward adjustment is limited by the stopping of the lower end 25 of the slide afainst the shoulder' 26 on the back-shank. T 1e back-slide is locked in any desired osition of adjustment by turning the ham ledscrew against the friction-block and forcing the same againstl the bottom of the backl shank channel on each side of the roove, and the slide can be freely remove from the shank by turnin the screw outward far normally enough to free its inner end from the bottom of the chai tel above .the groove therein. The back is also adjusted on its pivot by means of thc pendent rack 27 preferably lo cated in the crotch of the tent 29. The yoke is pre erably mounted on the same ivot 17, which connects the back proper witili its slide, and hanvs down against the forward face of the backliank, by which arrangement the rack is free to go up and l down with the slide in its various ad'ustments. 'lhe dctent is pivoted to the hack l proper adjacent to the rack, and by entering 1t into the various notches of the rack the back propel' is held at various points olt rotation on its pivot. ilie extension or tail l0 is l rovided on the lower end of the yoke of sufi `cient length to bear against the i'orward face of the backshank when the slide is adl justed upward to the limit ol' its movement; l and this tail may be curved forward at its lower' ond 3l so as to be moved lorna rd by i and dellected in front ol' the rounded upper l end 32 of the seat` bracket, when the back, l the slide and the shank are lowered toward t the limit ol' their movement. 'l'his dellec l tion of the tail ol the yoke hns the eil'eot of tilting` the lower part ol' thc hack proper foi-j l wardwhen its shank is adjusted. downward l l i l oke 28 and the de- 1 oi' the seat racket.

The head-rest 3? is formed or attached on the upper end of the shank 3l which in torn is located, longitudinally adjusted and locked in the channel 35 in the rear sidt .il'

the back-slide in the same manner that the back-slide is located, adjusted and lockt-d in the Isimilar channel of the back-slnmk- The l'rnme .'33 otE the secondary est if; pivotally connected to the i'ranie l ol' the ordinary seat by means ol' the parallel connecting bars .54 and 55. one o'l` which is located at each end oi' the seat and rcspet tively near the rear and lornardsidcs t hcrcol. The upper end oi' the l'ornard liars are preferably provided \\ith the handles .Eo hy means ol' which tl'e secondary seat may he raised on its pivotal connections from its normal prone position, as indicated by broken lines in Fic. -l, to its position for use as shown by fulllines in the saine figure.

lhel'rame 1 of the ordinary seat is preferably lilled in by suitable )lates as 57 and 5S so as to provide a suitalile foot rest for a child using the secondary seat, and the secondary seat may be held in. its raised position by means of the brace links 59 which are pivoted together with the upper ends of the rear connecting bars 54 to the seat frame, and at the lower free end are provided with the notches 60, which notches are adapted to engage over the shrinks of the headed pins 61 on the lower parts ol' the forward connecting bars 55, when the secondary seat is raised to its position for use. To lower the seat it is only r-ieccssztry to disengage these notches from the pins, whereuion the scat is free to be moved liorwart and downward on.its pivotal connections. The secondary seat thus lowered is normally nested under and covered by the ordinary `seat cushion of the chair, which same is removed when the seeondny scat is to be used.

A convenient 4manner of making the seeoin|ar \v seat is to connect the upper parts oll the i'o|'\.'ard connecting bars 55 with the pivotal rod ti?, and to provide the hall' journal hearings o3 in the upper side ot the sent l'rnme fill, in which bearings the 'rod is adapted lo be located, after which the cushion-plato till is rivcted on the upper side ol the frame thus` holding the pivotal rod in its bearing. And the upper ends ol' the rear conrecting lnir and the brace links may be connected to the frame on pivot to secupe by Letters the back, which may be adjusted to and.

from the seat as may be desired. y

The secondary seat shown and described, but not claimed herein, is made the subjectmatter 'of a divisional applicationA which has matured in Letters Patent,No. 891,762, dated June 23, 1908.

What I claim as m invention, and desire atent, is-

1. In a chair, afseat frame having a rearwardly extending bracket, a shank having an endwise slidable connection with the bracket, a back having a pivotal connection on the shank, and a curved extension on the back normally resting against the shank and adapted to be defiected by the seatbracket when the back is lowered toward the seat-frame.

2. In a chairfa seat frame with a cushion thereon and having a channel therein curved on the arc of a circle having its center located over the seat cushion approxi'- Inately in the position of the hip joint of an occu ant, a back with a headrest thereon and aving a curved shank ada ted to operate in the channel whereby t e head rest travels substantially in ,the locus of the occuants head, and means for locking the shank 1,. 1n the channel.

3. In a chair, a seat, a back with a head rest thereon, a`slidable connection between the seat and the back comprising a channel on the one curved on the arc of a circle g. having its `center located over the seat approxima'tely in the position of the hip ]oint of an occupant, a curved shank on the other ada ted to operate endwise in the channel wiiereby the head rest travels substantially in the locus ofthe occupants head, `and means for locking the shank in the channel.

4. In a chair, a seat frame with a cushion thereon and having a channel therein curved on the arc of a circle having its center located over the seat cushion approximately in the position of the hip joint of an occuiant, and a back with a head rest thereon aving a curved shank adapted to operate in the channel whereby the head rest travels subtantially in the locus of the occupants hea 5. In a chair, a seat, a back with a head rest thereon, and a slidable connection between thc seat and the back comprising a channel on the one curved on the arc of a circle having its center located over the seat approximately in the position of the hip joint of an occupant, and a curved shank on the other adapted to operate endwisc in the cpannel whereby the head rest travels subantially in the ylocus of the occupants head.

' In testimony whereof I have signed my name t this speciiication in presence of two subscribing Witnesses.

. FRANK E. CASE.

Witnesses:

HARRY FREASE, MINNIE F. ANTHONY. 

